Skip to content

Question

An electromagnetic wave in vacuum has an electric field amplitude of \( 30 \, \text{V/m} \). What is
the magnetic field amplitude? (Given \( c = 3 \times 10^8 \, \text{m/s} \))

Options

Choose one · Correct answer highlighted

Explanation

**Relationship E and B** in EM wave E₀ = c B₀, B₀ = E₀/c, for vacuum. Fields sustain each other via Maxwell's equations ∇×E = -∂B/∂t, ∇×B = μ₀ ε₀ ∂E/∂t, time-varying E produces B and vice versa, self-sustaining propagation without medium, speed c. Using B₀ = (E₀/c) , we have B₀ = (30/3 × 10⁸) = 1 × 10⁻⁷ T . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 1 × 10⁻⁷ T, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Discussion

Comments

0 comments

No comments yet. Be the first to start the discussion.